A negative electrode including a negative electrode active material layer, in which the negative electrode active material layer includes a silicon-containing negative electrode active material and a conductive material, the silicon-containing negative electrode active material includes a core and a carbon layer on the core, the core includes SiO.sub.x, wherein 0<x<2 and at least one metal atom, the at least one metal atom includes at least one selected from the group consisting of Mg, Li, Al, and Ca, the silicon-containing negative electrode active material has a D.sub.5/D.sub.50 of 0.5 or more, a D.sub.5 of 3 μm or more, and a D.sub.50 of 4 μm or more and 11 μm or less, and the conductive material includes single-walled carbon nanotubes, and a secondary battery including the negative electrode.

A silicon-containing negative electrode active material including a core and a carbon layer disposed on the core, in which the core includes SiO.sub.x, wherein 0<x<2 and at least one metal atom, the at least one metal atom includes at least one selected from the group consisting of Mg, Li, Al and Ca, D.sub.5/D.sub.50 is 0.5 or more, D.sub.5 is 3 μm or more, and D.sub.50 is 4 μm or more and 11 μm or less, a negative electrode including the same, and a secondary battery including the same.

Provided are a negative electrode, which includes a current collector and a negative electrode active material layer disposed on the current collector, wherein the negative electrode active material layer includes a conductive material, a negative electrode active material, and a binder, the negative electrode active material includes a silicon-based active material having a convexity of 0.8 or more as measured using a particle shape analyzer, and the convexity is defined by the following Formula 1, and a secondary battery including the negative electrode.

Convexity (C.sub.x)=Convex hull perimeter (P.sub.c)/Actual perimeter (P)   [Formula 1]

A secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive-electrode active substance layer, the positive-electrode active substance layer contains a pre-lithiation agent, and a molecular formula of the pre-lithiation agent is Li.sub.xNi.sub.aCu.sub.1−a−bM.sub.bO.sub.2, where 1≤x≤2, 0<a<1, and 0≤b <0.1, and M is selected from one or more of Zn, Sn, Mg, Fe, and Mn. The negative electrode includes a negative-electrode active substance layer including graphite and silicon-containing material. The electrolyte contains fluoroethylene carbonate (FEC). A weight percentage of the pre-lithiation agent in the positive-electrode active substance layer, a weight percentage of silicon content in the negative-electrode active substance layer, and a weight percentage of FEC in the electrolyte satisfy 0.2×W.sub.Si≤W.sub.FEC≤7.5%-0.6×W.sub.L.

The present invention relates to a cathode active material for a secondary battery and a manufacturing method thereof. A cathode active material, according to one embodiment of the present invention, comprises silicon-based primary particles, and a particle size distribution of the silicon-based primary particles is D10≥50 nm and D90≤150 nm. The cathode active material suppresses or reduces tensile hoop stress generated in lithiated silicon particles during a charging of a battery to thus suppress a crack due to a volume expansion of the silicon particles and/or an irreversible reaction caused by the crack, such that the lifetime and capacity of the battery can be improved.

A multilayer anode includes an anode collector, and a plurality of anode mixture layers sequentially stacked on at least one surface of the anode collector, and including natural graphite as an anode active material. A weight ratio of the natural graphite in innermost and outermost anode mixture layers is greater than a weight ratio of the natural graphite in an anode mixture layer located between the innermost and outermost anode mixture layers, in a stacking direction of the plurality of anode mixture layers. Performance of a cell may be improved and calendering-calender contamination occurring in a calendering process and an electrode stripping phenomenon may be prevented.

A miniature electrochemical cell having a total volume that is less than 0.5 cc is described. The cell casing is formed by joining two ceramic casing halves together. One or both casing halves are machined from ceramic to provide a recess that is sized and shaped to contain the electrode assembly. The opposite polarity terminals are electrically conductive feedthroughs or pathways, such as of gold, and are formed by brazing gold into tapered via holes machined into one or both ceramic casing halves. The two ceramic casing halves are separated from each other by a metal interlayer, such as of gold, bonded to a thin film metallization layer, such as of titanium, that contacts an edge periphery of each ceramic casing half. A solid electrolyte of LiPON (Li.sub.xPO.sub.yN.sub.z) is used to activate the electrode assembly.

An electrode material for a lithium ion secondary battery and method of forming the same, the electrode material including composite particles, each composite particle including: a primary particle including an electrochemically active material; and an envelope disposed on the surface of the primary particle. The envelope includes turbostratic carbon having a Raman spectrum having: a D band having a peak intensity (I.sub.D) at wave number between 1330 cm.sup.−1 and 1360 cm.sup.−1; a G band having a peak intensity (I.sub.G) at wave number between 1530 cm.sup.−1 and 1580 cm.sup.−1; and a 2D band having a peak intensity (I.sub.2D) at wave number between 2650 cm.sup.−1 and 2750 cm.sup.−1. In one embodiment, a ratio of I.sub.D/I.sub.G ranges from greater than zero to about 1.1, and a ratio of I.sub.2D/I.sub.G ranges from about 0.4 to about 2.

A negative active material for a rechargeable lithium battery includes a core including a SiO.sub.2 matrix and a Si grain, and a coating layer continuously or discontinuously coated on the core. The coating layer includes SiC and C, and the peak area ratio of the SiC (111) plane to the Si (111) plane as measured by X-ray diffraction analysis (XRD) using a CuKα ray ranges from about 0.01 to about 0.5.

(a) A battery including a power storage element and an electrolytic solution is assembled. (b) Initial charging is performed on the battery. (c) Alternate charging and discharging are performed on the battery after the initial charging. In the alternate charging and discharging, charging and discharging are alternately performed once or more respectively at a voltage between 4.0 V and 4.1 V and a current rate of 0.6 C or higher. The total number of times of charging and discharging is 3 or greater. The charging is performed such that the voltage changes by 0.05 V or higher and 0.1 V or lower whenever the charging is performed once. The discharging is performed such that the voltage changes by 0.05 V or higher and 0.1 V or lower whenever the discharging is performed once.